Can you keep a thermos in the fridge?

It is generally not recommended to keep a vacuum-insulated thermos in the refrigerator or freezer, as extreme temperature changes may damage the structure and performance of the container over time.

A thermos is designed to maintain the temperature of its contents, keeping them hot or cold for an extended period. Frequent exposure to extreme temperature fluctuations like placing it in the fridge after use can put stress on the materials and affect its effectiveness in insulation.

However, if you have a stainless steel thermos without a glass liner, you can sometimes keep it in the refrigerator for short periods. It is important to ensure that the thermos is completely sealed and that no liquid can leak out. Additionally, it's worth noting that the effectiveness of the thermos in keeping liquids cold may be reduced after being in the fridge.

It's always best to check the manufacturer's instructions and recommendations for your specific thermos to ensure its proper use and longevity. Some thermoses may have specific guidelines regarding refrigeration, so it's important to follow those instructions to avoid any damage.

If you need to cool the contents of a thermos, it is safer and more effective to place the liquid you want to cool directly in the refrigerator or freezer rather than putting the entire thermos inside.